Scratch - Uranus Explorer 2 {Scratch}

Scratch Uranus Explorer 2 Original Design / Scratch Built

Scratch - Uranus Explorer 2 {Scratch}

Contributed by Tom Markel

Construction Rating:
Flight Rating:
Overall Rating:

Published:	2011-08-14
Manufacturer:	Scratch
Style:	Ring/Tube/Cone Fin

Brief

Personal Challenge: A workin' model built from and themed on Toilet Paper Rolls, matey, Rear Ejection (of course!) and fly-able with C engines

Components

8 High-Quality Toilet Paper Roll Centers*
BT 5
BT 20
Foam Board t' make Adapter Rings
Maskin' Tape (lots and lots o' Maskin' Tape)
Rubber Bands for Shock Cord
Standard 12 inch parachute

(*Regardin' "High Quality Toilet Paper Rolls," t' cores from t' industrial strength extra large rolls used in hospitals and office buildings by professional janitorial services are thicker, smoother, and tougher than t' stuff you get at t' grocery store. Well, blow me down! T' spirals are however very deep.)

Construction

Challenge: Build a rocket based on theme o' Uranus Explorer (but keep it PG rated)

At t' same time I was buildin' t' rocket (actually t' second rocket, me hearties, t' Uranus Explorer 1 was a dismal failure) I be makin' up a story that went along with t' rocket. Avast, me proud beauty! Begad! I think t' best place t' put that is up front in this review, so here it is.

INTERSPACE TELEX FROM SPACE COMMAND

URGENT: You have been ordered t' take IMMEDIATE command o' t' Uranus Explorer II.

BACKGROUND: In t' first half o' t' 21st century, concerns on Earth mounted regardin' global warming. Ya scallywag! While thar be a great uproar about changin' human behavior t' combat this menace, matey, me bucko, t' problem solved itself in t' second half o' t' century. Avast! While t' well-meanin' efforts o' t' "Greens," as they came t' be called, arrr, may have had some impact, matey, t' finite supplies o' fossil fuels expired by 2075. Avast, me proud beauty! In addition, me hearties, shiver me timbers, shiver me timbers, t' fight t' obesity epidemic, t' fast grub enterprises were vilified by t' population. Avast! Avast, matey, me proud beauty! Ronald McDonald be hung in effigy in several countries. Begad! Blimey! Since beef hamburgers were t' main stock in trade for these restaurants, t' demand for beef largely expired with t' fast grub franchises. Blimey! T' final major source o' greenhouse gasses, matey, t' cattle farms, also went t' way o' t' dinosaur. Aye aye! T' global warmin' scare was over.

T' loss o' cheap fuel and fast foods led t' a progressive sense o' dissatisfaction among t' people o' Earth, me bucko, who attempted t' drown their sorrows in entertainment. VCRs and DVD players gave way t' IPods, matey, Androids, shiver me timbers, me bucko, Playstations, ya bilge rat, me bucko, Wiis, and other devices, all o' which shared two features. First, ya bilge rat, they required electricity. Arrr! Second, they were a mindless waste o' time.

To replace t' fossil fuels, me bucko, t' people o' Earth maximized their use o' renewable energy sources, arrr, includin' Wind, shiver me timbers, Geothermal, me hearties, ya bilge rat, Hydroelectric, matey, and Solar. T' first three were largely limited by geography. Begad! Solar, however, was only limited by surface area. Arrr! By t' year 2125, me bucko, me hearties, solar "farms" had sprung up over much o' t' Earth’s surface, includin' Antarctica, matey, and floatin' solar "mats" covered much o' t' oceans. Avast, matey, me proud beauty! Low Earth Orbit solar satellites created a virtual "traffic jam" in t' skies, ya bilge rat, t' t' chagrin o' terrestrial astronomers. Begad! Begad! Lookin' up at t' sky at night, more stars "moved" than remained in once place.

T' combination o' t' loss o' greenhouse gas generators and t' impact o' solar collectors shadin' much o' Earth’s surface as well as fillin' t' skies had an effect that should have been anticipated--- t' Earth's climate was headin' for a second Ice Age. Temperatures plummeted.

Many different plans t' restore t' greenhouse gas "blanket" were attempted. Ahoy! A nationwide chili marathon be probably t' most grandiose. Aye aye! It had little effect on t' global atmosphere, me bucko, me hearties, but resulted in numerous hospitalizations throughout t' state o' Texas dues t' t' accumulation o' noxious gases. Begad! Well, blow me down! In desperation, t' people o' Earth looked t' t' skies for help. Blimey! Ya scallywag! T' United States, me hearties, ya bilge rat, once an importer o' fossil fuels, arrr, now developed a plan t' import greenhouse gases from space.

Of t' four planetary gas giants, t' highest concentrations o' methane are found around Uranus, at roughly 2% o' t' atmosphere by volume. Avast, me proud beauty! Blimey! While further away than Saturn and Jupiter, me bucko, ya bilge rat, manned expeditions t' Uranus in 2186 found t' planet had a rocky core with numerous central caverns. Avast, me proud beauty! Concentrations o' methane within t' caverns approached 75%. Unlike Saturn and Jupiter, t' caverns could be sealed, cleared o' t' methane, heated, matey, and pressurized. In other words, thar could be life inside Uranus.

Drillin' operations began in 2192, shiver me timbers, me hearties, and t' planet be formally colonized under t' leadership o' Admiral Ezekiel Koli in 2199. Begad! T' fecundity o' E. Begad! Koli's descendents became legendary, and within 5 years t' colonists had spread throughout t' bowels o' t' planet. Blimey! Arrr! Methane gas generated within t' rocky core was diverted t' natural "vents" on t' planet surface. This gas be collected in Surface Repositories (dubbed "SuPositories.") T' SuPositories were then harvested by tanker ships and t' gas was transported t' Earth. T' effort has been thus far successful. Earth's temperatures have stabilized and are gradually returnin' t' 21st century levels. Avast! T' only casualty be t' state o' Utah, matey, matey, which seceded from t' Union when t' restoration o' "normal" temperatures forced them t' maroon plans for year-round skiing.

Durin' t' drillin' operations on Uranus, me bucko, miners discovered rich deposits o' Amodium. Existin' in two chemical isomers, t' "L" or levo form and t' "D" or dextro form, me bucko, Uranian Amodium be predominantly in t' D isomer. Blimey! Valued for its medical properties, me bucko, Amodium-D is extremely useful in t' treatment o' dysentery. Avast! Earth's Amodium supplies were exhausted in t' early 21st century in a vain attempt t' stem t' tide o' large fecal outflows from Washington, D.C. Uranus produces 80% o' t' pharmaceutical grade Amodium-D in t' solar system. T' only other major supply o' Amodium-D is in t' asteroid belt. Ya scallywag! Tanker ships, notorious for poor hygiene, me hearties, were plagued with dysentery and t' production o' Amodium around Uranus rivaled t' methane minin' operations in profitability.

T' growin' population inside Uranus yearned for t' same amenities and distractions as their distant Earthly cousins. Avast! Entrepreneurs, ever anxious t' make a credit, established venues on t' Uranian satellites, includin' a Disney Theme Park, "Part o' Your World," on t' satellite Ariel, shiver me timbers, a Lane Bryant Woman's Clothin' outlet store on t' satellite Titania, shiver me timbers, and a romantic bed and breakfast getaway, ya bilge rat, "A Quiver o' Love" on t' satellite Cupid. Avast, me proud beauty! Well, blow me down! By 2250, Uranian commerce had established a respectable amount o' regularity.

Unfortunately, t' hygienic habits o' t' Tanker Man-O-War crews did nay improve. Due t' failure in interspace decontamination procedures, ya bilge rat, one or more tankers have carried a type o' "animal fungus" from t' asteroids t' t' surface o' Uranus. Ya scallywag! Avast, me proud beauty! Blimey! These vile creatures reproduce rapidly and are incredibly adherent t' t' rock and ice surface o' t' Uranian core. Begad! Blimey! They are particularly attracted t' t' relative heat around t' vents o' Uranus. Ahoy! Dubbed, me hearties, "Cling-Ons" by t' colonists, t' invaders have destroyed t' SuPositories and have multiplied t' t' extent that they are now obstructin' many o' t' methane outlets. Ahoy! T' buildup o' pressure behind t' vents is reachin' dangerous levels, producin' dyspepsia, ya bilge rat, matey, arrr, nausea, and vomitin' among t' population o' t' planet. Minin' operations o' Amodium-D have ground t' a halt. Avast! Blimey! Because thar be no local supply, me hearties, me hearties, an outbreak o' dysentery on t' satellite Oberon has required importation o' Amodium from t' asteroid belt. This has put an incredible load on an already strained interplanetary supply system.

T' situation is now CRITICAL.

We have deployed Remotely Operated Infrared Detectors (ROIDs) within all t' major vents t' monitor t' situation. T' ROIDs will detect focal temperature increases which herald obstruction. Avast! Blimey! Additional SuPositories have been prepared t' replace those destroyed by t' Cling-Ons. Well, blow me down! T' Jovian and Saturnine Fleets have been redirected t' assist in t' emergency.

T' initial scout ship, shiver me timbers, t' Uranus Explorer, me hearties, was mothballed in 2195. Begad! It has been recommissioned for t' rescue effort. Arrr! T' previous BVD-1 subspace engine has been upgraded t' t' BVD-2. Begad! T' Man-O-War has also been augmented by 4 Procto and Gamble Sharmin "Ultra" outboard engines t' give it interplanetary capability at 0.25 light speed.

Your mission is as follows:

Rendezvous with t' USS Colon Powell (commanded by Admiral Sigmoid Koli) and guide t' Fleets in t' evacuation o' Uranus.
Scour Uranus and wipe out t' Cling-Ons.
Monitor t' ROIDs. Begad! At any hint o' sensitivity, insert t' replacement SuPositories t' relieve t' obstructed vents.
Restore Amodium-D minin' operations, t' reduce t' frequency and urgency o' the runs betwixt t' asteroids and Uranus.

Addendum: On successful completion o' this mission, you and your spouse are authorized a 30 day furlough at t' "Quiver o' Love" on Cupid. Avast, me proud beauty! Remember, with 27 satellites, thar be always a full moon around Uranus.

END TRANSMISSION

Back t' t' review. Avast! Ahoy! Blimey! Goals o' t' rocket buildin' were as follows:

Had t' look at least slightly cool
Use Toilet Paper rolls for much or all o' construction
Rear End Ejection (naturally)
Inexpensive project
Standard (A, me hearties, B, or C) Engine size (see #4)
Write a background story.

After buildin' t' Estes Porta-Pot Shot, shiver me timbers, and readin' notes from a reviewer who suggested a rear-ejection model, started t' think o' other designs sort o' on t' same theme. Arrr! Original design became t' Uranus Explorer 1 (UE1), (which will be fairly similar t' t' UE2, described here. Ahoy! Blimey! I found that usin' only two rolls for t' nose-cone fuselage combo resulted in a stubby rocket that I could nay get stable (I know, ya bilge rat, matey, I built it and tried. For some reason Tim Van Milligan doesn't have Toilet Paper tubes in t' RockSim inventory. Arrr! Go figure!) So t' lengthen t' fuselage, ya bilge rat, had t' use two rolls connected (alternative would have been t' use a single paper towel roll, ya bilge rat, but that would have violated t' theme. Ya scallywag! Would have had t' call it t' Brawny or t' Scrubber, or somethin' else. Aye aye! But I digress...) You say, no problem, arrr, a coupler would work for this. Problem, ya bilge rat, ya bilge rat, since I pre-determined t' use aft end ejection, ya bilge rat, I needed a pristine smooth inner contour, so a (standard) internal coupler wouldn't work. Aye aye! Ahoy! So I went with an external coupler. Ahoy! Blimey! This o' course was aerodynamically suboptimal, but since I wasn't plannin' t' set an altitude or duration records, me hearties, was acceptable. Begad! So I used an external coupler cut from another tube. I figured I would put t' launch lug in t' gap later (had I really thought it through, me bucko, would have remember I could hide a launch lug in t' tube fins.) This still left a small step-off or "transition" on t' inside where t' two tubes butted together. I ran maskin' tape from end t' end along t' inside so that thar were no transitions t' trap or catch t' engine pod and recovery devices durin' aft ejection.

Next problem: t' nose cone. First, ya bilge rat, me bucko, nay sure that toilet paper roll centers really come in a standard size for nose cones. Ahoy! Ahoy! Second, ya bilge rat, I'm cheap. Avast, me proud beauty! Avast, me proud beauty! Third, wanted t' keep overall weight o' t' body o' t' rocket light (more on this later.) 4rth, wanted t' use as many TP rolls as possible. Aye aye! Wondered---- how could I make a nose cone out o' a toilet paper roll?

By cuttin' 16 length-wise cuts nearly t' t' end o' t' roll, then cuttin' a diagonal out o' each section, me bucko, I be able t' create a roughly Ogive cone. Aye aye! Ya scallywag! Connected t' tips with tape. Blimey! Put a "shoulder" (again cut from another TP roll) on t' anterior end o' t' body tube. Attached this with CA t' t' previous two tubes I now have a fuselage (one-piece with t' nose cone) just under three TP rolls long I then ran strips o' maskin' tape LENGTHWISE from just beyond t' tip t' just aft/tailward o' t' nose-cone/fuselage joint). At t' tip, matey, me hearties, I cut the corners steeply and wrap around t' nose cone. Ahoy! Blimey! I had t' run a few spiral wraps for support and t' maintain shape.

Nose Cone

Shoulder

Nose Cone/Fuselage

Finishing

As mentioned, t' buildin' and paintin' run together as t' paintin' be done before completely fittin' together t' parts.

Once I had t' shape roughed out, it was time t' fill. Aye aye! However, I wanted t' have a shipshape paint job with different colors for t' fuselage and t' tube fins. Begad! I felt that maskin' would be tough. Avast, me proud beauty! But if I painted them first, then I would be tryin' t' glue together painted surfaces. Avast, me proud beauty! Ya scallywag! That didn't sound like it would be t' strong. Begad! On t' other hand, shiver me timbers, I KNEW exactly where all t' joints would be (I be usin' four tube fins, matey, shiver me timbers, paired, on opposite sides o' t' fuselage. Aye aye! Since 6 tubes would fit perfectly, arrr, matey, I just placed marks at 60 degrees, 120 degrees, arrr, ya bilge rat, me hearties, 240 degrees, shiver me timbers, and 300 degrees on t' fuselage. Blimey! Begad! On t' tube fins, two marks each, shiver me timbers, shiver me timbers, 60 degrees apart, matey, would suffice. Arrr! Avast! For increased stability, I let 1/2 o' t' tube fins lag behind t' end o' t' fuselage (also thought would look cooler. Arrr! Later durin' actual preparation o' t' rocket for launch I found it did make access t' t' engine mount awkward.) So marked on all t' tubes where t' joints should be. I also marked where I wanted t' put t' launch lug.

I wanted t' "protect" t' joint areas from t' paint and sealer t' set up a stronger joint. Ya scallywag! Blimey! On t' UE1 I had placed thin strips o' maskin' tape over these areas. Ahoy! Blimey! I discovered t' maskin' tape broke down under t' sandin' process, ya bilge rat, so I tried Mylar tape strips, me hearties, 1/4 inch wide. I placed a "tail" over t' edge/lip o' each tube, and then wrapped t' very tip INSIDE t' tube. Ahoy! Blimey! Turned out t' sandin' still wore off most o' t' tails, me bucko, but t' tip piece wrapped inside was an adequate marker for removal o' t' tape later. Ya scallywag! Blimey! Each strip was 1/2 t' length o' a single tube.

It took five coats/sandings o' Elmer's filler t' get a good smooth surface over t' nose-cone maskin' tape. Ahoy! Therefore regardin' "savin' money" as a reason t' make your own nose cone--Unless your time is worth less than 25 cents an hour, shiver me timbers, you’re better off buyin' it from Tim. Ya scallywag! But since this WAS a themed rocket, me hearties, me bucko, me bucko, it seemed worth it. Well, blow me down! (Although me lovely wife wasn't happy about t' pile o' filler dust on t' front porch!) I need three coats/sandin' t' fill t' DEEP VALLEYS o' t' toilet paper roll spirals anyway, matey, (another reason t' use REAL body tubes.) I sealed t' tube fins (outside only) t' same way.

Note that since this is a rear-ejection model, it allowed me t' cover t' nose-cone/fuselage joint. While I was fillin' in t' maskin' tape defects and t' tube spirals, arrr, it turns out I had enough filler t' cover t' external coupler. In fact, by t' time I be done t' slight residual "bulge" be hardly notice-able. Ya scallywag! Blimey! (Performance-minded rocketeers are probably shudderin' at t' added weight o' t' filler required t' accomplish THAT.)

When I be finished, I had a very nice fuselage with a smooth surface from tip t' tail, arrr, except for t' "break" in t' external coupler where I planned t' put t' launch lug. Avast, me proud beauty! Again, had I been thinking, me bucko, I would have filled this in too and put hidden t' lug in t' tube fin/fuselage joint. Avast! I believe t' absence o' a nose-cone/fuselage transition gives t' rocket a retro Buck Rogers look. Blimey! O' course, I also believe in t' tooth fairy. Again, I digress......

I knew that tryin' t' fill in t' INSIDE spirals o' t' tube fins was goin' t' be hopeless. Ya scallywag! I figured t' insides o' a spaceflight engine would probably look a little "charred", so I planned on paintin' t' inside flat black and hoped that would hide t' defects.

Okay, so paintin' now comes before actually completin' construction. Before starting, arrr, I peeled back t' edges o' t' Mylar at t' distal edges o' t' tubes, t' make sure I could find them after paintin' (paintin' t' inside would obscure t' "tails" I had wrapped on t' inside o' t' tube.) T' hard part was FINDING t' edge. Ya scallywag! Many o' t' "tails" that I had thought would provide "handles" had been sandin' off durin' finishing. But t' tips that I had wrapped on t' inside (unsealed) part o' t' tubes were still there. Ya scallywag! Well, me bucko, blow me down! Usin' them as guides, I used an Exacto cutlass t' peel back t' edges o' t' Mylar tape on t' OUTSIDE so I could find it after paintin' t' inside. Arrr! Arrr! I wrapped newspaper around t' OUTSIDE o' t' tube fins, ya bilge rat, tapin' it at t' edges/lips. Then I used flat black paint t' finish t' INSIDE o' t' tubes. Avast, me proud beauty! I actually tried rolled up sandpaper t' reduce t' "nap" inside t' tube, but it didn't work very well. Begad! Avast, me proud beauty! Primer would have helped, but I be havin' a struggle justifyin' tryin' t' prime t' INSIDE o' t' engines. Begad! Again, I figured I be goin' for style, me bucko, matey, nay performance, arrr, so I gave up on that part. Blimey! I sort o' liked t' internal "charred" look o' t' engines. As a prior Air Force guy, I noticed t' nozzles o' jet engines on t' flight-line often had blackened look, me bucko, matey, so I felt I was okay with it for space engines.

Color Scheme: All t' pictures o' t' PLANET Uranus showed it t' be a bluish color, so I figured I'd stay with this.

I primed t' fuselage with Krylon White Primer, three coats, me hearties, with light sandin' betwixt coats. Avast! This filled in t' few defects I had left after t' Filler. I used Krylon True Blue for t' fuselage - I really like t' color this gave, me hearties, me hearties, and I was happy with t' finish here.

After paintin' t' inside o' t' tube fins black, I took off t' outer maskin' paper. I then rolled up paper INSIDE t' tubes t' mask t' insides. Blimey! This allowed me t' "stack" t' tubes, which actually made paintin' t' outside easier. Ahoy! I had run out o' primer, so I went directly t' paintin' t' outside o' t' tubes Blue Ocean Breeze. I did 3 coats, with a light sandin' betwixt coats. I liked this color as well. Well, blow me down! Well, me bucko, blow me down! Although I hadn't thought it out ahead o' time, I remember t' three colors that were common for bathroom tiles in t' 60s--- pastel yellow, ya bilge rat, pastel pink, ya bilge rat, and pastel blue. Avast, me proud beauty! This looked pretty close t' t' pastel blue, matey, shiver me timbers, connectin' t' planetary and Toilet Paper theme.

Moment o' truth, what would happen when I peeled off t' Mylar? Actually, I be quite pleased with t' sharp edges. Well, blow me down! Pullin' t' tape off also raised some more "nap" off t' cardboard tubes, exactly what I wanted t' "rough it" for gluing.

As I had expected, me hearties, despite t' masking, ya bilge rat, thar was a little bleedin' o' black and blue (no pun intended) at t' edges o' t' tube fins. Avast! Blimey! Begad! Blimey! I used thin strips o' silver Mylar tape t' cover/accent t' edges here and at t' trailin' end o' t' fuselage. Avast! Blimey! As a USAFA grad, t' silver and blue together got me right under t' old squadron patch, as me Dad, a retired AF Navigator/Bombardier says. Begad! Blimey! I wrapped t' edges o' t' tape into t' inside o' t' tube. Begad! Blimey! Lookin' back, this gave t' edge a bit o' a rough look; I probably would just have put it on t' OUTSIDE only, just up t' t' edge.

Now that this was finished, ya bilge rat, me bucko, time t' see how things fit together. Well, blow me down! Well, blow me down! I used medium CA t' glue 4 tubes into two tube-fin pairs, me bucko, ya bilge rat, placin' t' glue along one o' t' "naked" strips previously covered by Mylar. Layin' t' tubes flat gave me a good alignment. I then matched up t' remainin' strips on each tube pair with t' strips on each side o' t' tail o' t' fuselage. They matched up pretty well, and t' medium CA gave me enough time t' make sure t' alignment was perfect. Begad! Avast! I got a pretty solid joint (as I later proved in flight, ya bilge rat, but more on that later.) Fillets weren't needed, and t' fit covered t' "naked" areas.

I pried t' Mylar tape out o' t' defect in t' external coupler. Well, ya bilge rat, blow me down! Blimey! This left a rougher edge.I glued in t' launch lug.If I had t' do it over, I would have pulled this off AFTER doin' t' filler step, but BEFORE painting, me bucko, t' get a better look.

Next question, me bucko, ya bilge rat, where t' attach t' shock cord? If I attached it inside, me hearties, matey, it would get hit by t' ejection charge fairly directly, me hearties, and would also cause problem with slidin' out t' motor pod. Aye aye! Avast! Perhaps more importantly, matey, matey, if it came out t' tail, ya bilge rat, t' rocket would fall nose first. Arrr! Begad! My launch site is about 3/4 grass, arrr, 1/4 asphalt. Blimey! Invariably t' better t' finish on t' rocket, t' more likely it will land on t' asphalt. Begad! Also, arrr, while t' cardboard/maskin' tape/Elmer's Finish nose cone was holdin' t' finish well, shiver me timbers, I could feel that it be still a little "soft" and didn't think it would hold up t' a hard impact. Blimey! Finally, I figured if I could get t' rocket t' descent in a horizontal position, me hearties, t' rocket body itself would be addin' t' t' drag and slow it down.

With t' rocket painted, t' CG o' t' rocket body was right at t' region o' t' external coupler. Aye aye! I threaded a needle with me Keelhaul®©™ shock cord into t' tube just above t' coupler next t' t' launch lug, me bucko, me hearties, and pull about two feet out t' after end o' t' fuselage. Ya scallywag! I then threaded a needle with t' ENDS o' a long loop o' dental floss through a hole just BELOW t' coupler and out t' aft end o' t' fuselage. Avast, me proud beauty! Begad! I then threaded ANOTHER loop o' floss (loop 2) through this loop, and pulled loop 2 through t' hole and out t' tail, keepin' t' ENDS o' loop 2 outside fuselage. Avast, me proud beauty! Avast! I then used loop 2 t' pull t' shock cord BACK into t' tail o' t' fuselage and back through t' hole below t' coupler (there probably is an easier way t' do this, shiver me timbers, but this is what I came up with.) I then tied a tight "loop" o' shock cord, ya bilge rat, runnin' it just next t' t' launch lug, leavin' about 1 1/2 feet o' Keelhaul®©™ loose. Ya scallywag! Yes, this loop DID run inside t' rocket body, when t' engine pod would slide in and out, me hearties, shiver me timbers, but t' cord be runnin' longitudinally and wouldn't obstruct/catch on t' pod. Arrr! Blimey! I did add a bit o' thin CA t' secure it.

Since I wasn't sure how well me hollow nose cone would hold up t' t' Estes engine ejection blast, I cut a bulkhead out o' foam board and place it inside t' body. Ya scallywag! Begad! It slid up t' t' "shoulder" that had been placed on t' front o' t' body tube. Ahoy! Ejection blast would hit t' bulkhead, matey, but nay t' "formed" shape inside o' t' nose cone. Well, blow me down! Begad! Instead o' gluin' it into place, I placed a length o' Keelhaul®©™ on this in case I needed t' pull it out later (such as t' add nose weight), and left that loose.

Engine Pod: I originally planned t' use a length o' BT20 as an engine mount AND pod. Well, blow me down! Well, blow me down! However, after buildin' it, me bucko, I discovered I wanted more room for me parachute and streamer. Ya scallywag! I used a BT20 for an engine mount. I then wrapped t' end o' a BT5 with electrical tape until it just fit inside t' BT20. Blimey! Well, blow me down! T' BT5 acted as BOTH an engine block AND a duct t' direct t' ejection force t' t' front o' t' body, me hearties, where it hit t' bulkhead. Arrr! Arrr! I used foamboard t' cut adapter rings for t' BT20 at t' tail and t' BT5 at t' front o' t' body. Begad! These were sanded t' slide loosely, but hopefully t' front one would be tight enough t' seal t' ejection charges away from t' chute and streamer. Ya scallywag! Lookin' back, I probably should have used two adapter rings up front, ya bilge rat, as a little bit o' ejection charge snuck around t' front rin' and slightly charred t' streamer.

I had initially planned on a long white "simulated TP" streamer t' recover t' rocket (in keepin' with t' theme). However, shiver me timbers, early on it be clear that given t' weight o' t' rocket a streamer would never safely slow t' rocket AND t' engine pod. Also, ya bilge rat, again I knew t' nose cone was a little bit "soft" and wanted t' cushion t' landin' o' t' body as much as possible. Arrr! My solution had two parts. Aye aye! First, allow t' engine pod t' completely separate from t' body o' t' rocket, arrr, ya bilge rat, matey, so t' two descend separately. Aye aye! This reduced t' weight o' t' body o' t' rocket (with t' soft cone). Ya scallywag! If I needed nose weight, I could add it t' t' front o' t' pod, rather than t' body. Begad! This is a NICE trick with aft ejection boost gliders, ya bilge rat, by t' way. Avast, me proud beauty! Blimey! You can adjust your CG by addin' weight t' t' front o' t' ejection pod, me hearties, without affectin' t' weight or CG o' t' glider itself. Aye aye! Then I could use me white streamer t' safely recover t' engine pod (which wasn't really very delicate and was nay that heavy), and a parachute t' recover t' body. T' shock cord for t' body was attached t' OUTSIDE o' t' fuselage at t' CG, shiver me timbers, thus t' body descended horizontally under t' chute.

I used two pieces o' white crepe paper t' create t' streamer for t' body tube. I attached them side by side with silver Mylar tape. I then accordion folded this into squares t' simulate toilet paper sheets. Ya scallywag! T' silver tape showed on one side, matey, which I thought would be easy t' see (on t' off chance this bird flew outside me launch site-- yeah, matey, right.) T' other side was straight white, which looked like, matey, me hearties, well, toilet paper. Blimey! Well, arrr, blow me down! While for t' real theme this would be "rolled" around t' engine pod "spindle", arrr, me experience is that this is unlikely t' "unroll" in flight durin' descent. Ya scallywag! Therefore I stayed with t' accordion fold. Ya scallywag! Aye aye! I used a length 10 times width, arrr, shiver me timbers, accordin' t' Stine's book o' optimal streamer length, me bucko, me hearties, arrr, then added a couple o' inches t' give me space t' attach it t' t' BT5 section o' t' pod.

I used a couple o' thick rubber bands t' link t' parachute t' t' Keelhaul®©™ shock cord attached t' t' mid section o' t' exterior body o' t' rocket.

Note: Originally I used Tim Van Milligan's Model Rocket Design & Construction book t' make two semispherical parachutes, shiver me timbers, arrr, me bucko, then "ironed" t' two together side t' side. Avast, me proud beauty! Begad! T' idea be t' create a parachute with a "cleft" down t' middle, t' so called "glute chute." (For those who have actually intentionally fallen out o' perfectly good aircraft, ya bilge rat, thar be a parachute malfunction called a "Mae West" that looks somewhat similar.) However, me bucko, while t' parachute looked good, the "glute chute" didn't pack very tightly, and even reducin' t' engine pod diameter from BT20 t' BT5 didn't give me enough room t' actually use this. Well, blow me down! Aye aye! I made an 8-line 12-inch chute out o' a green garbage bag (okay, was gettin' tired o' t' theme at this point.)

Construction Score: 2

Flight

Moment o' truth arrived. Would this work?

First "gotcha" be t' prep. Blimey! T' overhangin' 4 tube fins may (or may not) look cool. Ahoy! They do however obstruct access t' t' tail o' t' body. Arrr! Avast, me proud beauty! Blimey! This is bad enough when all you have t' do is stuff an engine in, arrr, matey, but when you have t' shove in t' entire engine pod with t' accordion streamer AND t' parachute up t' rear, arrr, those overhangin' tubes REALLY get in t' way.

Anyway, ya bilge rat, seemed like a C6-3 engine would probably be a good start for this.

Loaded it up on a nearly windless sunny day. Arrr! Crossed me fingers. Begad! Begad! Fired. Boost be arced t' t' left (not sure if this was due t' some uneven-ness o' t' fins.) Made it t' roughly 150 feet, at apogee be travelin' nearly horizontal. Ejection was at or near apogee. Avast, me proud beauty!

Recovery

Perfect separation o' pod and body. Aye aye! Begad! Streamer extended nicely and at 36 inches long, matey, shiver me timbers, 3 inches wide, me bucko, ya bilge rat, white and silver, was quite visible. Arrr! Chute also opened well. Ahoy! Rocket was far away at this point, but t' descent be either horizontal or slightly tail down (just what I wanted, me bucko, t' protect that nose!) Pod and body landed about 100 yards from pad, ya bilge rat, about 10 yards apart, me bucko, on t' grass. Avast, me proud beauty! Absolutely no damage from t' fall. T' white streamer was very slightly singed.

Had I been smart, I would have counted me blessings and put t' rocket on t' shelf at this point. However, ya bilge rat, me hearties, I'm nay smart. I decided t' try it again. Arrr! On flight two t' engine pod apparently caught on somethin' (may have been packed too tight.) Probably me combined two tubes were nay as smooth internally as a single standard store-bought tube would have been. Aye aye! Begad! Negative ejection. Ahoy! Lawn dart. Nay sure any nose cone would have come thought this unscathed, but me (five coats o' filler, multiple hours o' sanding, multiple coats o' paint - whimper whimper) nose cone accordioned. Ya scallywag! Nay fixable.

Flight Rating: 4

Summary

Pros:

I had fun, arrr, ya bilge rat, probably as much writin' t' background story as buildin' and flyin' t' rocket.
T' paper/maskin' tape/filler nose cone came out well, and I think I may use this again for aft ejection models (but will start with a REAL body tube!) Also particularly nice for a large but light nose cone. Avast! T' nose finishes well and looks great
Rear Ejection worked well. Ahoy! Downsizin' t' central "duct" from BT20 t' BT5 works great and gives you extra space for your recovery device(s). Ahoy! T' BT5 also functions as an engine block. No waddin' required. . Again, me bucko, you can use t' long engine pod t' add any needed weight far forward on t' engine pod (and thus anterior on t' rocket in boost phase) to brin' t' CG forward on boost phase without addin' weight t' t' glider at separation.
Separatin' t' pod from t' body allows t' more delicate body t' descend slower.
T' Mylar Mask Strips worked well in allowin' me t' pre-finish and pre-paint parts prior t' assembly, shiver me timbers, arrr, but still allow a strong joint. Wonderin' if this might work on an Estes Outlander that I have yet t' build. Suggestions would be welcome.
External shock cord attachment at CG allowed model t' descend horizontally. That a horizontal descent position adds more drag on descent is already well known. Well, blow me down! However it also allowed me t' avoid t' soft nose hittin' ground, which would be t' normal orientation for a rear-ejection model. Aye aye! Begad! This technique may be useful in rockets where certain parts o' more fragile than others. Arrr! You can adjust t' attachment position t' make it less likely these parts will directly impact t' ground on recovery. Blimey!
Stayed with Planet Uranus/Toilet Paper Theme
Parts were cheap (until you think o' t' time it takes for extra finishing)
It WORKED! (well, at least once.)

Cons:

Paper/Tape/Filler nose cone is slightly soft. Blimey! It requires a bulkhead t' protect it from ejection charge and should nay be allowed t' directly hit t' ground on descent (especially nay ballistically.)
External Shock Cord is a bit difficult t' stuff into t' engine pod as you stuff t' engine pod into t' tail o' t' body.
Separatin' pod from body on recovery means you must track both (but t' pod falls pretty fast, me hearties, so shouldn't drift much.)
I couldn't leave well enough alone and stop with one flight.
For some reason t' white paper streamer kept catchin' on me heel.

Overall Rating: 4